Directive antenna system



June 6, 1939.

H. o. PETERSON 2,160,899

DIRECTIVE ANTENNA 'SYSTEM Original Filed May 29, 1934 2 Sheets$h@et 1 DIRECTION OF SIGNAL TEA VEL l9 .lf i i /2 $3 T T B DIRECTION OF I S/GNAL TRAVEL a i I L "JP/5 ,l km)- INVENTOR +4.0. PETERSON ATTORNEY June 6, 1939.

H. O. PETERSON DIRECTIVE ANTENNA SYSTEM Original Filed May 29, 1934 2 Sheets-Sheet 2 V2 A r V W d l g i6 29 f 1 d I 1 Z8 1 1 s l I RECE/VE/Z 0D RECE/ VER WM 2 WM 29 1 -1 L J 1- 1 1 3 1 1 35 1 1 1 1 RECEIVER 51G. TRAVEL 4/6601) um um um um Mn k 39 I 5/6. TAA VEL RECE/l/ER ---{j@ 1 INVENTOR 'H.O. PETERSON ATTORNEY Patented June 6, 1939 DIRECTIVE ANTENNA SYSTEM Harold 0. Peterson, Riverhead, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Original application May 29, 1934, Serial No.

728,072, now Patent No. 2,095,078, dated Octoher 5, 1937. Divided and this application May 8, 1936, Serial No. 78,550

9 Claims.

This invention relates to improvements in directive antenna systems, and is a division of my United States Patent No. 2,095,078, granted October 5, 1937, on an application Serial No. 728,072, filed May 29, 1934.

The principles underlying the invention are described in connection with Fig. 1, which represents a side view of a well known form of receiving antenna. This figure illustrates, diagrammatically, the situation for a so-called vertically polarized signal arriving at the receiving antenna at an angle above the horizon designated a. The magnetic flux lines in such a case are perpendicular to the plane of the paper and advance in the directions of the arrows shown, from which it is apparent that the flux lines cut the antenna conductor Ill and induce a voltage therein which is longitudinal with respect to the conductor. This voltage will build up along the conductor toward the receiver II in the manner described in United States Patent No. 1,381,089, granted June 7, 1924, to Harold H. Beverage. There is also indicated above the antenna a triangle ABC, in which AB represents the distance of signal travel through space, and BC represents the corresponding length of wire traversed by the signal in the same length of time. Since the velocity of the ether wave is greater than that of the current Wave in the antenna, it will be seen that the distance travelled along the conductor is longer than the distance of signal travel in space; for which reason the signal voltages induced in the conductor will tend to lag behind the advancing signal in space. An optimum condition will thus result when this lag of the signal in the conductor, in going from one end to the other, amounts to approximately difference in the phase angle. Consequently there is an optimum relationship which exists between the length of the conductor, the angle of arrival (or), and the velocity of propagation in the conductor. It is an object of the present invention to make use of this optimum relationship, which is done in the various antenna designs described hereinafter.

Fig. 1 shows conventionally, a Well known form of antenna;

Fig. 2 illustrates the principles of the invention as applied to a directive antenna combination capable of receiving in a directive manner both the horizontal and vertical polarized component of the signal wave. Means for receiving and combining the signal from the two components is also shown.

Fig. 3 illustrates another type of receiving antenna combination capable of independently receiving both the horizontal and the vertical component; and

Figs. 4 to 8, inclusive, are other embodiments showing antennae in accordance with the principles underlying the invention.

Referring to Fig. 2, which illustrates a plan view of the antenna in which all the conductors are substantially parallel with the surface of the earth, there is shown a diamond shaped antenna l and a single wire antenna 2 symmetrically located with respect to the two halves of the diamond and joined thereto at its apex by means of a resistance 13 of a value equal to the surge resistance of the wire. Similarly, the two halves of the resistance l2 represent the surge impedances of the respective halves of the diamond. In the system of this figure, the vertically polarized component of the wave, received from the distant transmitting station, will induce a signal in all of the conductors. Since the signal components induced in the outside conductors of the diamond are obliged to travel a greater distance than those induced in the central conductor 2, it follows that the resultant in the central conductor 2 will be out of phase with the resultants accumulating in the outside conductors at the output end of the antenna. A voltage will thus appear between the central conductor and the two outside conductors considered as operating in parallel and this voltage may be transmitted over a transmission line I4 and received in a receiving circuit I5. Thehorizontally polarized component of the received waves will cause a voltage to appear between the two outside conductors of the diamond I at the output end, i. e., the end joined to the transmission line M. This voltage is available at the receiver represented as I 6. Both the receivers l5 and [6, herein shown diagrammatically in box form, incorporate the usual amplifying and selective circuits commonly used in receiving practice. In these receivers the signal is finally passed into detectors, the outputs of which are combined at H. The relationship between the angles of the wires and the lengths of the conductors may be so chosen as to give optimum conditions of signal voltage at the output end leading to the receivers I5 and 16. Signals arriving from the reverse direction will be damped out by means of the network comprising surge impedances l2 and I3. It should herein be noted that impedance I3 is connected to the midpoint of impedance I2.

' Since the operation of the receiving circuits forms no part of the present invention per se,

vertically polarized component of the transmitted wave will be picked up on the two outer side wires 21, 22 of the rectangular shaped combination and on the transmission line 20 in the center thereof. The cross connection 23 for the two wires 2!, 22 introduces a phase change suflicient to produce a voltage due to the vertical component, which voltage finally reaches receiver I5 through the transmission line system l4. As in Fig. 2, the combination damping network l2, l3 at the far end serves to prevent reflection of signals arriving from the reverse direction.

The operation of the side or outer wires 21, 22 of Fig. 3 is more clearly understandable from a reference to Fig. 4, which illustrates an antenna system comprising, three parallel conductors 24, 25, 26. The incoming signal received on these conductors will build up voltages simultaneously on all three of these conductors. At the output end connected to the transmission line leading to the receiver, the resultant from the two outside wires 24, 26 is caused to travel through an additional section of line whereby there is obtained an appreciable change of phase with the consequent production of the effect of a voltage difference appearing between the two conductors of the transmission line. Such a phase change may be obtained by physically spacing the two out side conductors a distance D, approximately onehalf wavelength at the operating frequency and cross connecting these conductors by linear Wires 21, 28. If desired, conductors 24, 25, 26 may be spaced closer together, and the cross connecting conductors 2T, 23 bent in such manner as to provide sufficient length to produce the desired phase change. A resistance 29 at the far end of conductor serves as a damping impedance. If

it is desired to have a minimum of voltage picked up in the transmission line 30, there may be employed a shielded type of line comprising a surrounding metallic sheath 3! which is continuously grounded, as indicated.

Fig. 5 represents an antenna in which the traveling wave front builds up a voltage in two conductors 32, 33, one of which (33) is staggered and is longer than the other so that at the output end there is obtained a phase difference between the resultants in the two conductors. A damping impedance 29 connects the far. ends of the two wires 32, 33 of the antenna system together.

Fig. 6 similarly comprises two conductors 34, 35 which are joined together at their far ends by a damping resistance 29, one of the conductors being arranged to pick up signal voltages which are caused to have a lower phase velocity than the voltages in the other conductor by the addition of elements 36 connected thereto, these elements merely introducing capacitance between the conductor 34 and the earth. In this way the resultant voltage built up in one wire of the two will lag behind that of the other wire and there will accordingly appear a voltage difference between 34 and 35 at the output end leading to the' receiver.

Fig. 7 shows a conductor system comprising two wires 31 and 38 connected together at their ,far ends by a damping impedance 29 wherein conductor 31 is made to have a lower phase velocity by the introduction of series inductances 39 which are spaced apart along the length of the conductor. This inductance may, in some cases, be introduced in the form of a continuous body of magnetic substance in close proximity to the conductor. V

It is known that the earth acts as a reflector for the radio waves in much the same way as an ordinary mirror functions with respect to light waves} and also that for certain types of soil there is a critical angle at which no reflection of the vertical polarized component occurs. Long Island soil, for example, at Riverhead, has a critical angle of approximately 19 above the horizontal, and it will thus be evident that if an antenna is designed for the reception of the 19 vertically polarized component, it may be situated at an elevation much closer to the earth than has been the general practice in antennas designed to receive other components. For which reason it is proposed, in some cases, to design the receiving antenna and so position it near the surface of the earth as to exclude to a large extent all the other components except the 19 vertically polarized component. Such an antenna system is very economical to build because of the absence of the necessity for using high structures, and is superior for the reception of ultra high speeds of transmission since it discriminates against many undesired components, thus tending to eliminate troubles due to multipath phenomena.

It may be advantageous to run the transmission line parallel to and directly under the antenna system for a considerable distance, so that the natural directivity of the transmission line system itself will be along the same direction as that of the antenna structure. Fig. 8 shows such an arrangement wherein the two symmetrical sides 40 and 4| of the diamond antenna are connected together at the two apices, and connect at one end through a surge impedance with the middle wire 2. At the other end, wire 2 and the two side wires 20 and 4| in parallel are connected to a pair of down leads 42 which, in turn, connect to the transmission line 43, carrying the signal to thecreceiving station 44.

It is to be understood that the antenna systems of the invention may be used for transmitting as well as receiving and are not limited to the precise arrangement of parts shown since various departures from the systems illustrated may be employed within the scope of the invention.

What is claimed is:

1. In a high frequency receiving system, an antenna comprising a rectangular shaped conductor system, a pair of wires extending longitudinally of the length of said rectangular system and in the same plane thereof, an impedance connecting together the ends of the wires and another impedance connecting together the first impedance intermediate its ends to said rectangu-- lar system, a plurality of aerial elements spaced apart along the length of said pair of wires and capacitively coupled thereto, said aerial elements being disposed within the area of the rectangle formed by said conductor system, and means for separately obtaining the energies received by said rectangular system and said aerial elements and combining them.

2. A system in accordance with claim 1, characterized in this that said aerial elements comprise doublets.

3. An antenna system 'comprising .a' pair of amount at the ends of wires extending substantially in the direction of the received wave, high frequency translating apparatus coupled to said wires, said pair of wires being joined together at their ends farthest away from said high frequency apparatus by a damping impedance, and inductances spaced apart along the length of one of said wires for enabling the waves received on said one wire and accumulated along the length thereof to differ in phase from the waves received by the other of said wires and accumulated along the length thereof by a predetermined amount. 7

4. An antenna system comprising a pair of wires extending substantially in the direction of the received wave, high frequency translating apparatus coupled to said Wires, said pair of wires being joined together at their ends farthest away from said high frequency apparatus by a damping impedance, and aerial elements directly connected to only one of said wires and spaced apart along the length of said one wire for enabling the waves received on said one wire and accumulated along the length thereof to differ in phase from the waves received by the other of said wires and accumulated along the length thereof by a predetermined amount.

5. In a receiving system having a receiver and an antenna including two parallel conductors, the method of operation which comprises receiving waves on bothof said conductors, building up increments of voltage of the same polarity on said conductors due to said received waves, causing the increments of voltage produced in one of said conductors to lag continuously along the length of said one conductor with respect to the increments of the voltage produced in the other of said conductors until there is substantially 180 difference in phase angle between the resultant voltages on said two conductors which are available for utilization purposes, deriving energy from between said two conductors, and applying same to said receiver.

6. An antenna system comprising a pair of wires extending substantially in the direction of the received wave, high frequency apparatus coupled to said wires, said pair of wires being joined together at their ends farthest away from said high frequency apparatus by a damping impedance, and means in circuit with only one of said wires for enabling the waves received on said one wire and accumulated along the length thereof to differ in phase from the waves received by the other of said wires and accumulated along the length thereof by a predetermined high frequency apparatus, whereby the resultant the wires coupled to the energies collected by said wires combine to produce a magnified voltage in said high frequency apparatus.

7. In a receiving antenna system having two conductors extending in the general direction of travel of the wave to be received and which are coupled together at both their ends, the method of operation which comprises building up increments of voltage of the same polarity on said conductors from components of said received wave as said wave travels along the lengths of said conductors, and causing the resultant energy in one of said conductors, which is available for utilization purposes, to continuously lag behind the resultant energy in the other of said conductors by a predetermined amount.

8. In a high frequency receiving system, an antenna comprising a rectangular shaped conductor system, a pair of wires extending longitudinally of the length of said rectangular system and substantially in the same plane thereof, an impedance connecting together the ends of the wires and another impedance connecting together the first impedance intermediate its ends to said rectangular system, a plurality of aerial elements spaced apart along the length of said pair of wires and coupled thereto, said aerial elements being disposed within the area of the rectangle formed by said conductor system, and means for separately obtaining the energies received by said rectangular system and said aerial elements and combining them.

9. In a unidirectional receiving system having a receiver and an antenna including two conductors extending substantially the same distance toward the source of the wave to be received and coupled together at their ends nearest said source, the method of operation which comprises receiving waves from said source on both of said conductors, building up increments of voltage of the same polarity on said conductors due to said received waves, causing the increments of voltage produced in one of said conductors to lag continuously along the length of said one conductor with respect to the increments of voltage produced in the other of said conductors until there is substantially 180 difference in phase angle between the resultant voltages on said two conductors which are available for utilization purposes, preventing the building up of voltages on said conductors from waves received from a direction opposite to that of the source, deriving the energy from between said two conductors and applying same to said receiver.

HAROLD O. PETERSON. 

